You're probably right, but I think it's important to note the difference between Touch ID (a user feature) and ARKit (a developer feature). Users won't know or care about ARKit if developers don't adopt it.
Developers are to ARKit what merchants are to Apple Pay. Users wouldn't care about Apple Pay if merchants didn't take it as payment.
Exactly right. This isn't for iPads, it's for glasses two years from now.
Actually based on rumours the glasses were coming soon like this year.
This is the most relevant post in this thread. Holding up an iPad for hours pointing it at a table to play Millenium Falcon animated chess makes very little sense, but it will be incredibly cool when your friends can all sit around the table with their Apple Glasses on, and see the same AR projection :)